Ants comprise 5% of the world's 100 worst invasive alien species and 28% of land invertebrates (see Lowe S., et al., (2000). 100 of the World's Worst Invasive Alien Species A selection from the Global Invasive Species Database. Published by The Invasive Species Specialist Group (ISSG) a specialist group of the Species Survival Commission (SSC) of the World Conservation Union (IUCN), 12 pp). It has been estimated that there are over twenty thousand ant species occupying every ecological niche as part of the structure of ecological communities (see Holldobler and Wilson, The Ants. Harvard University Press, Cambridge, 1990; Smith et al., Cold Spring Harb. Protoc. 4:1, 2009), and over 12,500 currently described (antbase.org, 15 Jan. 2010). However, some of the ant species, especially those moved through human activities to non-native locations, have become serious pests (see Lessard et al., Ecology 90:2664, 2009; Porter and Savignano, Ecology 71:2095, 1990). The Myrmicinae subfamily, for example, is the largest of the 21 extant subfamilies in the ants (Hymenoptera: Formicidae) (Bolton, Mem. Am. Entomol. Inst. 71:1, 2003). The Myrmicinae subfamily includes about 140 genera within the group, including species with a functional sting (such as, for example, ants in the genus Solenopsis, one of which is S. invicta, known as the “red imported fire ant,” and Myrmica rubra, also known as the European fire ant or common red ant), and fungus-growing ants (of the tribe Attini, e.g., leafcutter ants (genus Atta and genus Acromyrmex). Collectively and individually, these and other ant species are considered pests in commercial, agricultural, and residential settings, causing significant damage and injury to crops and livestock and a host of other economic sectors, as well as potential medical issues (e.g., humans and animals can develop hypersensitivity to fire ant venom that may result in anaphylactic shock and death).
Global commerce ensures that these invasive pest species, including social insects such as various ant species (e.g., imported/invasive fire ants) will be distributed to compatible habitats throughout the world. For example, it is estimated that imported fire ants currently infest hundreds of millions of acres in southern tier states and Puerto Rico and are spreading northward. As is the case for most exotic species, invasive fire ants were introduced without most of their natural enemies in their native South American range. As a consequence, fire ant populations in the United States are estimated to be about 5-10 times denser than in South America. In recent decades S. invicta, for example, has changed from an invasive pest ant in the United States to a global problem, with infestations occurring in Australia, Taiwan, Mainland China, Mexico, and many Caribbean Island countries. This invasive ant is estimated to be responsible for almost $7 billion annually in damage repair, medical care, and control costs in the United States alone. Broad ranging economic sectors are impacted by fire ants including households, electric and communication services, outdoor recreation areas, agriculture, schools, and other areas.
Limited options exist for biologically-based methods of controlling or eliminating invasive and native pest ant populations in urban and rural environments. These limited options are due, in large part, to reliance on conventional pesticides for control, which in turn creates environmental and health risks associated with such pesticides. The use of broad-spectrum, persistent insecticides has significant drawbacks in that the chemicals also kill other beneficial insects and may contaminate surface and ground water due to runoff as well as create other environmental concerns.
There thus exists an industrial, commercial, and public ongoing need to develop efficacious, novel, and safe compositions and control methods to alleviate these problems, particularly for the control of invasive fire ants, as well as other invasive ants and insects, which are also cost-effective and easily adaptable for widespread use.